The proposed research project aims to identify the putative additional factors required for the export of U snRNAs from the nucleus. Understanding the processes of nucleocytoplasmic transport are of central importance to the control of gene expression in eukaryotes, and understanding this process may provide new targets for treatment of disease. Viral infections which require entry of the virion into the nucleus, or export of viral products from the nucleus could be envisioned to provide a means to block production of crucial viral components, thus preventing harmful viral infections. The current data regarding U snRNA export suggests the presence of at least one additional factor for U snRNA export which may be regulated at the level of nucleocytoplasmic transport. By a combination of in vivo microinjection of Xenopus oocytes, and in vitro biochemistry, the experiments designed in this research proposal will uncover additional factors required for reconstitution of U snRNA export from Xenopus oocytes which have been compromised in this cellular process. Once identified the role this factor plays in the export of U snRNA and other RNAs will be characterized in Xenopus and other organisms.